DE112019005372T5 - FORM A FLOWABLE DIELECTRIC LAYER WITH A HIGH CARBON CONTENT WITH LOW PROCESS DAMAGE - Google Patents

Abstract

A method for producing a dielectric layer comprises depositing a first starting material on a substrate. The first starting material has a cyclic carbosiloxane group with a six-membered ring. The method also includes depositing a second starting material on the substrate. The first raw material and the second raw material form a preliminary layer on the substrate, and the second raw material comprises silicon, carbon and hydrogen. The method further includes applying energy from an energy source to the preliminary layer to form a porous dielectric layer.

Description

BACKGROUND

The present invention relates generally to manufacturing methods and resulting structures for semiconductor devices. More specifically, the present invention relates to manufacturing methods and resulting structures for flowable, high carbon dielectric layers formed with little process damage.

Integrated circuits in electronic units require the manufacture of semiconductor units. A sequence of photolithographic and chemical process steps creates the electronic circuits on a semiconductor wafer. The semiconductor wafers are subject to a front-end-of-line (FEOL) process sequence and a back-end-of-line (BEOL) process sequence. A FEOL process flow involves forming transistors directly in the silicon. A BEOL process sequence includes connecting the respective semiconductor units to one another in order to form the electrical circuits. In particular, interconnection metal wires separated by insulating layers are produced. The insulating dielectric material is, for example, silicon dioxide or materials with a low dielectric constant (k).

SHORT REPRESENTATION

Embodiments of the present invention are directed to a method of making a dielectric layer. A non-limiting example of the method includes depositing a first starting material on a substrate. The first starting material contains a cyclic carbosiloxane group which has a six-membered ring. The method also includes depositing a second starting material on the substrate. The first raw material and the second raw material form a preliminary layer on the substrate, and the second raw material comprises silicon, carbon and hydrogen. The method further includes applying energy from an energy source to the preliminary layer to form a porous dielectric layer. Advantages of the method include the provision of a smaller pore size than in the case of the carbosiloxane counterparts with an eight-membered ring, so that the k value is reduced and a lower capacity is provided.

und bei a, b, c, d, e und f handelt es sich jeweils unabhängig voneinander um eine Alkyl-Gruppe oder eine Alkenyl-Gruppe. Das Verfahren umfasst außerdem ein Abscheiden eines zweiten Ausgangsstoffs auf dem Substrat. Der erste Ausgangsstoff und der zweite Ausgangsstoff bilden eine vorläufige Schicht auf dem Substrat, und der zweite Ausgangsstoff weist ein lineares Carbosiloxan auf. Das Verfahren umfasst des Weiteren ein Einwirken einer Energiequelle auf die vorläufige Schicht, um eine poröse dielektrische Schicht zu bilden. Vorteile des Verfahrens umfassen eine geringere Porengröße als bei den Carbosiloxan-Pendants mit einem achtgliedrigen Ring, so dass der k-Wert verringert und eine geringere Kapazität bereitgestellt wird.Another non-limiting example of the method comprises depositing a first starting material on a substrate. The first starting material has the following structure:

and a, b, c, d, e and f are each independently an alkyl group or an alkenyl group. The method also includes depositing a second starting material on the substrate. The first starting material and the second starting material form a preliminary layer on the substrate, and the second starting material comprises a linear carbosiloxane. The method further includes applying an energy source to the preliminary layer to form a porous dielectric layer. Advantages of the method include a smaller pore size than the carbosiloxane counterparts with an eight-membered ring, so that the k value is reduced and a lower capacity is provided.

Another non-limiting example of the method comprises depositing a first starting material on a substrate. The first starting material has a cyclic carbosiloxane group. The method also includes depositing a second starting material on the substrate. The first starting material and the second starting material form a preliminary layer on the substrate, and the second starting material comprises a carbosilane with a ratio of carbon to silicon which is higher than 3: 1. The method further includes applying an energy source to the preliminary layer to form a porous dielectric layer. Advantages of the method include an enriched carbon content and a smaller pore size and thus a strong and stable bond within the layer, so that improved mechanical properties (e.g. density) and a reduced susceptibility to process damage are provided, such as those caused by etching and planarization.

Embodiments of the present invention are directed to a dielectric layer. One non-limiting example of the dielectric layer includes a covalently bonded network having atoms of silicon, oxygen, carbon, and hydrogen. The dielectric layer also has a cyclic carbosiloxane group and a bridging Si — CH ₂ —Si group. Advantages of the dielectric layer include an enriched carbon content and a smaller pore size and thus a strong and stable bond within the layer, so that improved mechanical properties (e.g. density) and reduced susceptibility to process damage, such as those caused by etching and planarization, are provided .

Another non-limiting example of the dielectric layer includes a covalently bonded network having atoms of silicon, oxygen, carbon, hydrogen, and nitrogen. The dielectric layer also has a cyclic carbosiloxane group and a bridging Si — CH ₂ —Si group. Advantages of the dielectric layer include an enriched carbon content and a smaller pore size and thus a strong and stable bond within the layer, so that improved mechanical properties (e.g. density) and reduced susceptibility to process damage, such as those caused by etching and planarization, are provided .

Other technical features and advantages are realized through the techniques of the present invention. In the following, embodiments and aspects of the invention are described in detail and are considered part of the claimed subject matter. For a better understanding, reference is made to the detailed description and the drawings.

Figure list

• 1 bis 6 einen Prozessablauf für die Herstellung einer dielektrischen Schicht in einer Halbleitereinheit gemäß Ausführungsformen der vorliegenden Erfindung abbilden, in denen:
• 1 eine Querschnittsseitenansicht eines strukturierten Substrats der Halbleitereinheit abbildet;
• 2 eine Querschnittsseitenansicht des strukturierten Substrats anschließend an ein Auffließen eines ersten Ausgangsstoffs und eines zweiten Ausgangsstoffs auf das strukturierte Substrat abbildet;
• 3 eine Querschnittsseitenansicht des strukturierten Substrats anschließend an ein Bilden einer vorläufigen dielektrischen Schicht auf dem strukturierten Substrat abbildet;
• 4 eine Querschnittsseitenansicht des strukturierten Substrats anschließend an ein Einwirken eines Stickstoff enthaltenden Ausgangsstoffs auf die vorläufige dielektrische Schicht abbildet;
• 5 eine Querschnittsseitenansicht des strukturierten Substrats anschließend an ein Einwirken einer Energiequelle auf die vorläufige dielektrische Schicht abbildet; und
• 6 eine Querschnittsseitenansicht der porösen dielektrischen Schicht abbildet, die auf dem strukturierten Substrat ausgebildet ist;
• 7 eine exemplarische elektronenmikroskopische Aufnahme abbildet, die eine in Gräben angeordnete dielektrische Schicht gemäß Ausführungsformen der vorliegenden Erfindung zeigt;
• 8 eine graphische Darstellung abbildet, die Dielektrizitätskonstanten von dielektrischen Schichten vergleicht, die mit einer und ohne eine Härtung durch ultraviolettes (UV) Licht gebildet wurden;
• 9A eine graphische Darstellung abbildet, die den atomaren Prozentsatz an Kohlenstoff (Atom-% Kohlenstoff) in einer dielektrischen Schicht gemäß Ausführungsformen der vorliegenden Erfindung zeigt;
• 9B eine graphische Darstellung abbildet, die den atomaren Prozentsatz an Kohlenstoff (Atom-% Kohlenstoff) in einer dielektrischen Vergleichsschicht zeigt; und
• 10 eine graphische Darstellung abbildet, welche die prozentuale Schrumpfung einer dielektrischen Schicht gemäß Ausführungsformen der vorliegenden Erfindung anschließend an eine Einwirkung von Ammoniak zeigt.

The specifics of the exclusive rights described herein are particularly indicated and clearly claimed in the claims at the end of the description. The foregoing and other features and advantages of the embodiments of the invention are apparent from the following detailed description in conjunction with the accompanying drawings, in which:

• 1 to 6th depict a process flow for the production of a dielectric layer in a semiconductor device according to embodiments of the present invention, in which:
• 1 depicts a cross-sectional side view of a patterned substrate of the semiconductor device;
• 2 depicts a cross-sectional side view of the structured substrate subsequent to a flow of a first starting material and a second starting material onto the structured substrate;
• 3 depicting a cross-sectional side view of the patterned substrate subsequent to forming a preliminary dielectric layer on the patterned substrate;
• 4th depicts a cross-sectional side view of the patterned substrate subsequent to exposure of the preliminary dielectric layer to a nitrogen-containing precursor;
• 5 depicts a cross-sectional side view of the patterned substrate subsequent to exposure of an energy source to the preliminary dielectric layer; and
• 6th depicting a cross-sectional side view of the porous dielectric layer formed on the patterned substrate;
• 7th FIG. 12 depicts an exemplary electron micrograph showing a trenched dielectric layer in accordance with embodiments of the present invention; FIG.
• 8th FIGURE 9 is a graph comparing dielectric constants of dielectric layers formed with and without curing by ultraviolet (UV) light;
• 9A Figure 12 is a graph showing the atomic percentage of carbon (atomic% carbon) in a dielectric layer in accordance with embodiments of the present invention;
• 9B Figure 13 is a graph showing the atomic percentage of carbon (atomic% carbon) in a comparative dielectric layer; and
• 10 Figure 12 is a graph showing the percent shrinkage of a dielectric layer in accordance with embodiments of the present invention following exposure to ammonia.

The representations shown here are illustrative. Many variations in the depictions or acts described herein can exist without departing from the scope of the invention. For example, the processes can be performed in a different order, or processes can be added, eliminated, or modified. In addition, the term “coupled” and variations thereof describes that there is a connection path between two elements and does not imply a direct connection between the elements with no intervening elements / connections between them. All of these variations are considered part of the description.

In the accompanying figures and the following detailed description of the described embodiments, the various elements shown in the figures are provided with two- or three-digit reference symbols. With a few exceptions, the most closely matched left digit (s) of the figure in which the respective element is shown for the first time.

DETAILED DESCRIPTION

For the sake of brevity, conventional techniques relating to the manufacture of semiconductor devices and integrated circuits (ICs) may or may not be described in detail herein. In addition, the various tasks and process steps described here can be integrated into a more comprehensive method or process with additional steps or additional functionality that are not described in detail here. In particular, various steps in the manufacture of semiconductor devices and ICs based on semiconductors are well known, and so many conventional steps are briefly mentioned here for the sake of brevity or are omitted altogether without providing the well-known process details.

Turning now to an overview of technologies more specifically relevant to aspects of the invention, insulation requirements become more stringent as line dimensions decrease in order to increase the speed and storage capacity of microelectronic devices (e.g., computer chips). Reduced size and dimensions in these units require a material with a lower dielectric constant k to minimize the RC time constant, where R is the resistance of the conductive line, C is the capacitance of the insulating interlayer dielectric, and C is inversely proportional to the distance and is proportional to the dielectric constant k of the ILD.

Many of the manufacturing steps for VLSI (Very Large Scale Integration) chips and ULSI (Ultra-Large Scale Integration) chips are carried out by means of a plasma-assisted chemical vapor deposition technique or a physical vapor deposition technique. The ability to produce a material with an ultra-low dielectric constant k using a plasma-enhanced chemical vapor deposition (PECVD) technique using previously installed and available process facilities thus simplifies the integration of the production process, reduces production costs and generates less harmful waste.

Furthermore, the thicknesses of the dielectric insulator layers decrease as the size of electronic devices becomes smaller. As a result, the dielectric layers are subject to an increased tendency to deteriorate or wear, known as time-dependent dielectric breakdown (TDDB).

Dielectric layers with an ultra-low dielectric constant k, which have atoms of silicon (Si), carbon (C), oxygen (O) and hydrogen (H) (SiCOH), can be non-porous or can be porous. In general, porous SiCOH layers have a lower dielectric constant k (e.g., k less than or equal to 3.0) than the corresponding non-porous layers. The k values of porous SiCOH layers are usually equal to about 1.8 to about 2.95, layers with a lower dielectric constant k having a higher porosity. Porous layers can be formed, for example, by introducing an unstable pore-forming group during the deposition of the preliminary layer structure, which is then removed by hardening.

Porous SiCOH layers with an ultra-low dielectric constant k can, however, have sub-optimal properties compared to corresponding non-porous dielectrics, such as, for example, a high breaking speed and stress as well as a low modulus and a low hardness. The SiCOH dielectric layers may also deteriorate as the dielectric constant k becomes smaller. As a result, many SiCOH layers with an ultra-low dielectric constant k are prone to process damage. For example, it is possible that the carbon content in common SiCOH layers is degraded during structuring and etching processes (e.g. during reactive plasma ion etching processes and plasma incineration processes based on oxygen). As a result, the layer can behave like porous silicon oxide and it is possible that it can be quickly removed by a common wet etching process, which can affect the control of dimensions during patterning. Furthermore, the k value of porous silica is easy to absorb moisture and has a much higher k value (e.g., k greater than 4.2). The porous oxide layer therefore increases the total k value and capacitance, as well as the reliability of the final unit. Plasma Induced Damage (PID) is a parameter that describes this type of deterioration in a dielectric layer.

Improved mechanical properties of SiCOH dielectrics with a low or an ultra-low dielectric constant k can be achieved by treating the SiCOH layers after the deposition. For example, curing or treatment using thermal energy, ultraviolet (UV) light, irradiation with an electron beam, a chemical energy or a combination of these energy sources is used to stabilize the dielectric material with a low or an ultra-low dielectric constant k and to improve the mechanical properties thereof. While such post-deposition treatments are possible, they add additional process steps and thus additional costs in the production of dielectric layers with a low or an ultra-low dielectric constant k. Accordingly, there is a need for a material for improved dielectric layers having an ultra-low dielectric constant, k, which is not prone to mechanical rework damage and which can be used to fill units of reduced size and dimensions.

SiCOH layers can be formed using CVD processes, in which starting materials are deposited on structured areas of a substrate. Starting materials that are used to form the layers include, for example, cyclic and linear organosilicon compounds (for example cyclic siloxanes such as octamethylcyclotetrasiloxane [(CH ₃ ) ₂ SiO] ₄ ) and linear tetramethyl orthosilicate (Si (OCH ₃ ) ₄ ). The starting materials form a layer that flows onto the substrate during deposition, so that it is easier to fill limited geometries.

Although SiCOH layers with an ultra-low dielectric constant k are desired, porous SiCOH layers with lower k values compared to corresponding non-porous materials can have sub-optimal mechanical properties, such as, for example, a high breaking speed and stress and a low modulus and a low hardness. Accordingly, these layers with an ultra-low dielectric constant k are prone to process damage, such as, for example, those caused by chemical mechanical planarization (CMP). Accordingly, there is a need for a material for improved dielectric layers having an ultra-low dielectric constant k that is not prone to mechanical rework damage and can be used to fill units of reduced size and dimensions.

Turning now to an overview of the aspects of the invention, one or more embodiments of the invention address the above-described weaknesses in the prior art by providing deposition methods that can be used in low k dielectric layers with a high carbon content (e.g. greater than 20%). Two starting materials are used to form the dielectric layers. The first starting material is a cyclic organosilicon compound which has a cyclic carbosiloxane group with a six-membered ring made up of three silicon atoms, which alternate with three oxygen atoms, or with an eight-membered ring made up of four silicon atoms that alternate with four oxygen atoms. The first starting material has a high carbon content. The second starting material is linear carbosiloxane or carbosilane with a high carbon content. Compared to cyclic starting materials with four silicon atoms (eg octamethylcyclotetrasiloxane), cyclic carbosiloxane starting materials with six-membered rings have a higher carbon content. In some embodiments of the present invention, the C: Si ratio is higher than 4: 1 and the C: O ratio is higher than 1. Once the first starting material and the second starting material are deposited on the patterned substrate, the preliminary layer can a nitrogen-containing starting material (eg ammonia (NH ₃ )) to both form a nitrogen-containing SiCONH layer and to reduce shrinkage of the layer. The preliminary layer is hardened to form the final porous layer.

The aspects of the invention described above address the weaknesses of the prior art by providing flowable, porous SiCOH and SiCONH layers with high carbon contents and low k values (e.g. lower than 3 according to one or more embodiments of the present invention , 0). The three silicon cyclic carbosiloxanes provide a smaller pore size than their four silicon counterparts, thus providing a reduced pore size that reduces the k value and provides less capacity. Due to the combination of a higher carbon content and a smaller pore size and thus a strong and stable bond within the layer, the layers have improved mechanical properties (e.g. density) and a reduced susceptibility to process damage, such as those caused by etching and planarization. The layers also have improved conformal coverage for filling small spaces in structured substrates.

Turning now to a more detailed description of aspects of the present invention, FIGS 1 to 6th a process flow for forming a dielectric layer on one or more trenches 102 having structured substrate 101 according to embodiments of the present invention. 1 forms a cross-sectional side view of the structured Substrate 101 from. The structured substrate 101 comprises a single or multiple layer material including, but not limited to, a semiconducting material, an insulating material, a conductive material, or any combination thereof. Non-limiting examples of semiconducting materials include Si, SiGe, SiGeC, SiC, GaAs, InAs, InP, and other III / V or II / VI compound semiconductors. The structured substrate 101 may also include a layered substrate such as Si / SiGe, Si / SiC, silicon-on-insulators (SOIs), or silicon germanium-on-insulators (SGOIs).

When the structured substrate 101 comprises an insulating material, the insulating material can be an organic insulator, an inorganic insulator, or a combination thereof comprising multiple layers. When the structured substrate 101 having a conductive material, the structured substrate 101 for example, polysilicon, an elemental metal, alloys of elemental metals, a metal silicide, a metal nitride, and combinations thereof comprising multiple layers. The structured substrate 101 may comprise a combination of a semiconducting material and an insulating material, a combination of a semiconducting material and a conductive material, or a combination of a semiconducting material, an insulating material and a conductive material.

The one trench or the several trenches 102 (or the spaces) in the structured substrate 101 are formed, for example, by etching. When viewed from the surface, the trenches 102 have any shape or dimension. The trenches 102 can be circular, oval, polygonal, rectangular, or can have a variety of other shapes. The trenches 102 have a height and a width that define an aspect ratio of height to width that is higher than 1: 1 (e.g. 5: 1 or higher, 6: 1 or higher, 7: 1 or higher, 8: 1 or higher, 9: 1 or higher, 10: 1 or higher, 11: 1 or higher, 12: 1 or higher etc.). In some embodiments of the present invention, the high aspect ratio is due to small gap widths of less than 32 nanometers (nm), less than 28 nm, less than 22 nm, or less than 16 nm. Although the 1 to 6th Embodiments of a structured substrate 101 represent, the substrate is not structured according to other embodiments. The layers described herein can be deposited on any substrate having any surface topology, including one that is planar or substantially planar.

2 forms a cross-sectional side view of the structured substrate 101 subsequent to a flow of a first starting material 204 and a second raw material 206 onto the surface of the structured substrate 101 from. The structured substrate 101 is arranged in a reactor chamber. Then become the first raw material 204 and the second starting material 206 which may be in the form of a liquid, a gas or a vapor, introduced into the chamber. Any suitable deposition method can be used, for example spin coating, plasma enhanced chemical vapor deposition (PECVD), thermal chemical vapor deposition, vapor deposition, or other methods.

With the first raw material 204 is a cyclic carbosiloxane that has atoms of silicon (Si), carbon (C), oxygen (O) and hydrogen (H). With the first raw material 204 According to some embodiments of the present invention, it is a six-membered ring made up of three silicon atoms, which alternate with three oxygen atoms. According to other embodiments of the present invention, it is the first starting material 204 around an eight-membered ring made of four silicon atoms, which alternate with four oxygen atoms.

und
bei a, b, c, d, e und f handelt es sich jeweils unabhängig voneinander um eine Alkyl-Gruppe oder eine Alkenyl-Gruppe. Gemäß einer oder mehreren Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkyl-Gruppe um eine Methyl-Gruppe, eine Ethyl-Gruppe, eine Propyl-Gruppe, eine Butyl-Gruppe oder eine Pentyl-Gruppe. Gemäß einigen Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkenyl-Gruppe um eine Ethenyl-Gruppe, eine Propenyl-Gruppe, eine Butenyl-Gruppe oder eine Pentenyl-Gruppe.According to one or more embodiments of the present invention, the first starting material comprises 204 the following structure:

and
a, b, c, d, e and f are each, independently of one another, an alkyl group or an alkenyl group. According to one or more embodiments of the present invention, the alkyl group is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. According to some embodiments of the present invention, the alkenyl group is an ethenyl group, a propenyl group, a butenyl group or a pentenyl group.

und
bei a, c und e handelt es sich jeweils um eine Methyl-Gruppe, und bei b, d und f handelt es sich jeweils um eine Ethenyl-Gruppe.According to one or more embodiments of the present invention, the first starting material comprises 204 the following structure:

and
a, c and e are each a methyl group; and b, d and f are each an ethenyl group.

und bei a, b, c, d, e und f handelt es sich jeweils unabhängig voneinander um eine Alkyl-Gruppe oder eine Alkenyl-Gruppe. Gemäß einer oder mehreren Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkyl-Gruppe um eine Methyl-Gruppe, eine Ethyl-Gruppe, eine Propyl-Gruppe, eine Butyl-Gruppe oder eine Pentyl-Gruppe. Gemäß einigen Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkenyl-Gruppe um eine Ethenyl-Gruppe, eine Propenyl-Gruppe, eine Butenyl-Gruppe oder eine Pentenyl-Gruppe.According to some embodiments of the present invention, the first starting material comprises 204 the following structure:

and a, b, c, d, e and f are each independently an alkyl group or an alkenyl group. According to one or more embodiments of the present invention, the alkyl group is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. According to some embodiments of the present invention, the alkenyl group is an ethenyl group, a propenyl group, a butenyl group or a pentenyl group.

In one or more embodiments of the present invention, the first starting material comprises 204 a ratio of carbon to silicon (C: Si ratio) which is higher than 2: 1. According to other embodiments, the first starting material has a C: Si ratio that is equal to about 3: 1 to about 9: 1.

With the second starting material 206 According to one or more embodiments of the invention, it is a linear carbosiloxane and it has atoms of silicon (Si), carbon (C), oxygen (O) and hydrogen (H). According to other embodiments of the present invention, it is the second starting material 206 is a carbosilane, and it has atoms of silicon (Si), carbon (C) and hydrogen (H).

The second raw material 206 also has a high carbon content. In some embodiments of the present invention, the ratio of C: Si is in the second raw material 206 higher than 3: 1. According to other embodiments, the ratio of C: Si is in the second starting material 206 equal to about 4: 1 to about 8: 1. In one or more embodiments of the present invention, the second starting material comprises 406 a ratio of carbon to oxygen (C: O ratio) that is higher than 4: 1. In other embodiments of the present invention, the second starting material comprises 406 has a C: O ratio higher than 1.

und bei g, h, i, j, k und I handelt es sich jeweils unabhängig voneinander um eine Alkyl-Gruppe, eine Alkenyl-Gruppe oder eine Alkoxyl-Gruppe. Bei der Alkyl-Gruppe handelt es sich bei einigen Ausführungsformen der vorliegenden Erfindung um eine Methyl-Gruppe, eine Ethyl-Gruppe, eine Propyl-Gruppe, eine Butyl-Gruppe oder eine Pentyl-Gruppe. Gemäß einer oder mehreren Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkenyl-Gruppe um eine Ethenyl-Gruppe, eine Propenyl-Gruppe, eine Butenyl-Gruppe oder eine Pentenyl-Gruppe. Gemäß einigen Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkoxyl-Gruppe um eine Methoxyl-Gruppe, eine Ethoxyl-Gruppe, eine Propoxyl-Gruppe oder eine Butoxyl-Gruppe.According to one or more embodiments of the present invention, the second starting material comprises 206 the following structure:

and g, h, i, j, k and I are each, independently of one another, an alkyl group, an alkenyl group or an alkoxyl group. In some embodiments of the present invention, the alkyl group is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. According to one or more embodiments of the present invention, the alkenyl group is an ethenyl group, a propenyl group, a butenyl group or a pentenyl group. According to some embodiments of the present invention, the alkoxyl group is a methoxyl group, an ethoxyl group, a propoxyl group or a butoxyl group.

According to one or more embodiments of the present invention, the second starting material comprises 206 the following structure:

According to other embodiments of the present invention, the second starting material comprises 206 the following structure:

und bei m, n, o und p handelt es sich jeweils unabhängig voneinander um Wasserstoff, eine Alkyl-Gruppe, eine Alkenyl-Gruppe oder eine Alkoxyl-Gruppe. Bei der Alkyl-Gruppe handelt es sich bei einigen Ausführungsformen der vorliegenden Erfindung um eine Methyl-Gruppe, eine Ethyl-Gruppe, eine Propyl-Gruppe, eine Butyl-Gruppe oder eine Pentyl-Gruppe. Gemäß einer oder mehreren Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkenyl-Gruppe um eine Ethenyl-Gruppe, eine Propenyl-Gruppe, eine Butenyl-Gruppe oder eine Pentenyl-Gruppe. Gemäß einigen Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkoxyl-Gruppe um eine Methoxyl-Gruppe, eine Ethoxyl-Gruppe, eine Propoxyl-Gruppe oder eine Butoxyl-Gruppe.According to some embodiments of the present invention, the second starting material comprises 206 the following structure:

and m, n, o and p are each independently hydrogen, an alkyl group, an alkenyl group or an alkoxyl group. In some embodiments of the present invention, the alkyl group is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. According to one or more embodiments of the present invention, the alkenyl group is an ethenyl group, a propenyl group, a butenyl group or a pentenyl group. According to some embodiments of the present invention, the alkoxyl group is a methoxyl group, an ethoxyl group, a propoxyl group or a butoxyl group.

According to one or more embodiments of the present invention, the second starting material comprises 206 the following structure:

und bei q und r handelt es sich jeweils unabhängig voneinander um Wasserstoff, eine Alkyl-Gruppe, eine Alkenyl-Gruppe oder eine Alkoxyl-Gruppe. Bei der Alkyl-Gruppe handelt es sich bei einigen Ausführungsformen der vorliegenden Erfindung um eine Methyl-Gruppe, eine Ethyl-Gruppe, eine Propyl-Gruppe, eine Butyl-Gruppe oder eine Pentyl-Gruppe. Gemäß einer oder mehreren Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkenyl-Gruppe um eine Ethenyl-Gruppe, eine Propenyl-Gruppe, eine Butenyl-Gruppe oder eine Pentenyl-Gruppe. Gemäß einigen Ausführungsformen der vorliegenden Erfindung handelt es sich bei der Alkoxyl-Gruppe um eine Methoxyl-Gruppe, eine Ethoxyl-Gruppe, eine Propoxyl-Gruppe oder eine Butoxyl-Gruppe.According to other embodiments of the present invention, the second starting material comprises 206 the following structure:

and q and r are each independently hydrogen, an alkyl group, an alkenyl group or an alkoxyl group. In some embodiments of the present invention, the alkyl group is a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. According to one or more embodiments of the present invention, the alkenyl group is an ethenyl group, a propenyl group, a butenyl group or a pentenyl group. According to some embodiments of the present invention, the alkoxyl group is a methoxyl group, an ethoxyl group, a propoxyl group or a butoxyl group.

According to one or more embodiments of the present invention, the second starting material comprises 206 the following structure:

During the first raw material 204 and the second starting material 206 are deposited, an oxidizing gas or an inert gas may be contained in the chamber. Non-limiting examples of oxidizing gases include carbon dioxide, oxygen, nitrous oxide, or any combination thereof. The oxidizing gas can be used to stabilize the reactants in the reactor and to improve the uniformity of the dielectric layer deposited on the substrate. The oxidizing gas is optional and can be used to aid reactivity and uniformity.

The conditions for the deposition of the first raw material 204 and the second raw material 206 may vary depending on the ultimate dielectric constant of the dielectric layer desired. However, the use of a low temperature provides a layer with a high carbon content by allowing at least a portion of the unstable organic pore-forming groups remain in the final layer. In accordance with one or more embodiments of the present invention, the temperature used can range from about 10 ° C to about 300 ° C. In a further aspect, the temperature can be specified with a temperature in a range from about 25 ° C to about 200 ° C. In still further embodiments of the present invention, the temperature can be specified at about 60 ° C to about 120 ° C.

3 forms a cross-sectional side view of the structured substrate 101 subsequent to forming the preliminary dielectric layer 303 from the first and the second starting material 204 , 206 on the structured substrate 101 from. The preliminary shift 303 has a covalently bonded network of silicon (Si), oxygen (O), carbon (C) and hydrogen (H) together with a cyclic carbosiloxane structure. The preliminary shift 303 also has, in accordance with some embodiments of the present invention, a bridging Si-CH ₂ -Si group from the second starting material 206 on.

The preliminary dielectric layer 303 forms a conformal layer that is on the surface of the patterned substrate 101 is generally uniform. The preliminary dielectric layer 303 fills the trenches 102 even with high aspect ratios, without creating air gaps or cavities in them.

The preliminary dielectric layer 303 also has an unstable pore former, a portion of which is then removed to form a final porous dielectric layer. A pore former is an unstable, removable functional group that is present in and covalently bonded to the temporary layer. At least a portion of the pore former is then removed by means of an energetic treatment step (see 5 ) is removed to provide the final porous layer with a low dielectric constant k. As mentioned herein, a porous dielectric layer has a plurality of pores or openings within the layer that are formed by the removal of a plurality of unstable pore formers.

4th forms a cross-sectional side view of the structured substrate 101 subsequent to the action of a nitrogen-containing starting material 410 on the preliminary dielectric layer 303 from. According to one or more embodiments, the nitrogen-containing starting material comprises 410 Ammonia (NH ₃ ). The starting material containing nitrogen 410 _{comprises nitrous oxide (D 2} O) according to some embodiments of the present invention.

By the action of the nitrogen-containing starting material 410 on the preliminary dielectric layer 303 a small amount of nitrogen (N) may or may not be added to the layers. Thus, the resulting layer is then exposed to the action of the nitrogen-containing starting material 410 Silicon, carbon, oxygen and hydrogen (SiCOH) or silicon, carbon, oxygen, hydrogen and nitrogen (SiCONH). The action of a nitrogen-containing raw material 410 on the preliminary shift 303 mitigates shrinkage of the layer and enables the layer to retain greater physical strength than an untreated, otherwise similar layer. Without being bound to a theory, the action of the nitrogen-containing starting material 410 increase the effectiveness of the subsequent hardening process, which can remove unwanted components and cross-link the layer matrix to form a rigid material lattice.

5 Figure 12 is a cross-sectional side view of the nitrogen treated preliminary dielectric layer 303a during curing with an energy source 505 from. To form the final porous layer with a low dielectric constant k (303b, as in 6th shown) becomes energy 505 in the form of thermal energy, UV light, microwaves, in the form of an electron beam, an ion beam or in the form of another energy source such as catalytic species on the preliminary dielectric layer treated with nitrogen 303a applied. In some embodiments of the present invention, a combination of two or more of these energy sources is used. This supplied energy converts the temporary dielectric layer treated with nitrogen 303a into the final porous layer with a low dielectric constant k µm (as in 6th shown). Specifically, removing at least a portion of the unstable pore-forming group from the preliminary layer provides a porous layer as described below. Due to the structure of the first raw material 204 With a cyclic carbosiloxane structure, for example, compared with other cyclic tetrasilane starting materials, for example octamethylcyclotetrasilane (OMCTS), smaller, essentially non-interconnected pores are provided. Because of the high carbon content of the second starting material, the carbon content of the final porous layer is also higher.

According to some In embodiments of the present invention, the temperature of the curing process is equal to about 100 ° C to about 450 ° C. In other embodiments, the temperature of the curing process is equal to about 200 ° C to about 400 ° C. According to one or more embodiments of the present invention, the temperature of the curing process is equal to about 250 ° C to about 385 ° C or equal to about 300 ° C to about 350 ° C.

Hence, at least some of the pore former is in the final layer 303b with a low dielectric constant k does not exist. In the energetic treatment step, pores or voids or holes are created in the final layer. The resulting final layer 303b with a low dielectric constant k has a porosity in the nanometer range, which is formed by removing the pore-forming groups.

The thickness of the layer 303b with a low dielectric constant k generally varies and is dependent on the desired application. According to some embodiments of the present invention, the layer 303b with a low dielectric constant k has a thickness of about 5 nanometers (nm) to about 500 nm. In some embodiments of the present invention, the layer has 303b with a low dielectric constant k has a thickness of about 20 nm to about 120 nm.

According to one or more embodiments of the present invention, the dielectric constant is (k) of the layer 303b with a low dielectric constant k lower than 3.0. In some embodiments of the present invention is the k-value of the layer 303b with a low dielectric constant k lower than 2.7. In yet another aspect is the k-value of the layer 303b with a low dielectric constant k lower than about 2.6. In yet another aspect is the k-value of the layer 303b with a low dielectric constant k equal to about 2.2 to about 2.8.

According to one or more embodiments of the present invention, it is the layer 303b with a low dielectric constant k around a SiCOH layer, and it has a covalently bonded network of atoms of Si, C, O and H on. The atoms form a three-dimensional network structure in which Si, C, O and H are connected to one another and are related to one another in the x, y and z directions. The layer 303b with a low dielectric constant k has a high percentage of carbon (C), which increases crosslinking in the layer. In addition, higher carbon content provides beneficial properties including lower plasma induced damage (PID), smaller mean pore size, and improved modulus. In some embodiments of the present invention, the layer has 303b with a low dielectric constant no bridging Si-CH ₂ -Si group.

In one or more embodiments of the present invention, the layer has 303b with a low dielectric constant k, an atomic percentage (atomic%) of carbon (C) of at least about 30 to (30 atomic% carbon (C)). In some embodiments of the present invention, the layer has 303b with a low dielectric constant k has at least 35 atom% carbon (C). In still further embodiments of the present invention, the layer has 303b with a low dielectric constant k has about 35 atom% carbon (C) to about 50 atom% carbon (C).

According to one or more embodiments, it is the layer 303b with a low dielectric constant k around a SiCONH layer, and it has a small amount of nitrogen (N), so that stability and PID are improved. In some embodiments of the present invention, the layer has 303b with a low dielectric constant k about 1 atom% nitrogen (N) to about 15 atom% nitrogen (N). In other embodiments of the present invention, the layer has 303b with a low dielectric constant k about 1 atom% nitrogen (N) to about 4 atom% nitrogen (N).

The chemical structure of the layer 303b having a low dielectric constant k improves the mechanical properties of the material. According to one or more embodiments of the present invention, the layer 303b with a low dielectric constant k at a thickness of 400 nm has a modulus of 3 gigapascals (GPa) to about 12 GPa. In some embodiments of the present invention, the layer has 303b with a low dielectric constant k at 400 nm has a modulus of about 7 GPa to about 10 GPa.

According to one or more embodiments of the present invention, the layer 303b with a low dielectric constant k has a porosity of about 1% to about 50%. According to some embodiments of the present invention, the layer 303b with a low dielectric constant k has a porosity of about 8% to about 20%.

The layers 303b with a low dielectric constant k can be used in a variety of applications. For example, the layers can be used in processes and devices with fully aligned vias, space-fill applications in FEOL gate stacks, and space-fill processes and devices. Units are used in magnetoresistive memories with random access and magnetic tunnel junction (MTJ MRAM).

EXAMPLES

7th forms an exemplary electron microscope image 700 a dielectric layer arranged in trenches in a substrate 702 according to embodiments of the present invention. At the shift 702 it was a SiCOH layer and it was about 80 nm thick with a k value of about 2.75. As shown, filled the layer 702 the high aspect ratio spaces between pillars in the substrate 707 . The spaces had an aspect ratio of 1: 1. The layer 702 filled the spaces with no evidence of voids.

8th forms a graphic representation 800 ab, which compares dielectric constants of dielectric layers formed with and without curing with ultraviolet (UV) light. The measurements were carried out at 150 ° C. In general, the dielectric layers 802 without UV curing, the k values are higher than those of dielectric layers 804 that have been UV cured. UV cure reduced the k values from about 2.8 to about 2.6.

9A forms a graphic representation 900 which shows an atomic percentage of carbon (atomic% or at .-% carbon) in a layer produced according to embodiments of the present invention, which layer is formed from a starting material having a cyclic carbosiloxane group with a six-membered ring of silicon and oxygen has been. 9B forms a graphic representation 901 which shows an atomic percentage of carbon (atom% or at% carbon) in a comparative dielectric layer formed from an octamethylcyclotetrasilane (OMCTS) starting material with an eight-membered ring of silicon and oxygen. As in the 9A and 9B shown is the atomic percentage (at.%) of carbon 904 the inventive layer higher (40 at .-% to 45 at .-%) ( 9A) as the atomic percentage (at.%) of carbon 903 the comparison layer, which was approximately equal to 30 at .-% ( 9B) .

10 forms a graphic representation 1000 showing percent shrinkage of a dielectric layer in accordance with embodiments of the present invention following exposure to ammonia. As shown, treating the layers with ammonia reduced the shrinkage of the layers.

Various embodiments of the present invention are described herein with reference to the accompanying drawings. Alternative embodiments can be devised without departing from the scope of this invention. While various connections and positional relationships (e.g., above, below, adjacent, etc.) between elements are set forth in the following description and in the drawings, one skilled in the art will recognize that many of the positional relationships described herein are orientation-independent if the functionality described is maintained even if the orientation is changed. These connections and / or positional relationships, unless otherwise specified, can be direct or indirect, and the present invention is not intended to be limiting in these respects. Accordingly, a coupling of entities can refer to either a direct or an indirect coupling, and a positional relationship between entities can be a direct or an indirect positional relationship. As an example of an indirect positional relationship, references in this specification to forming a layer “A” over a layer “B” include situations where one or more intervening layers (e.g., a layer “C ") Are located between layer" A "and layer" B ", as long as the relevant properties and functionalities of layer" A "and layer" B "are not significantly changed by the layer (s) in between.

The following definitions and abbreviations are to be used for the interpretation of the claims and the description. As used herein, the terms “has,” “having,” “comprises,” “comprising,” “has,” “having,” “contains,” or “including” or any other variation thereof are intended to be a non-exclusive inclusion cover. For example, a composition, mixture, process, method, article, or device that has a list of items is not necessarily limited to only those items, but may include other items that are not specifically listed or which are inherent in such a composition, mixture, process, method, article or device.

Additionally, the term “exemplary” is used herein to mean “serving as an example, case, or illustration”. Any embodiment or configuration described herein as "exemplary" is not necessarily preferred or advantageous over to interpret other embodiments or designs. The terms “at least one” and “one or more” are to be understood to include any integer greater than or equal to one, ie, one, two, three, four, etc. The term “A plurality” is to be understood to include any integer greater than or equal to two, ie, two, three, four, five, etc. The term “connection” can include an indirect “connection” and a direct “connection” .

References in the description to “the one embodiment,” “an embodiment,” “an exemplary embodiment,” etc. indicate that the described embodiment may have a particular feature, structure, or characteristic, but that each embodiment does special feature, which may or may not have the special structure or characteristic. In addition, such phrases do not necessarily refer to the same embodiment. Furthermore, when describing a particular feature, structure, or characteristic in connection with an embodiment, it should be considered that such feature, structure, or characteristic is well within the knowledge of one skilled in the art in connection with others To influence embodiments, regardless of whether explicitly described or not explicitly described.

For the purposes of the description in the following, the terms "upper / upper / upper", "lower / lower / lower", "right", "left", "vertical", "horizontal", "top", "bottom" refer to and derivatives of the same on the structures and methods described, as they are oriented in the drawing figures. The terms "overlying", "above", "on top", "positioned on" or "positioned above" mean that a first element, such as a first structure, is present on a second element, such as, for example, a second structure wherein there may be intervening elements between the first element and the second element, such as an interlayer structure. The term “direct contact” means that a first element, such as a first structure, and a second element, such as a second structure, are connected without any intervening conductive, insulating or semiconducting layers at the interface of the two elements.

The phrase "selective with respect to" such as "a first element selective with respect to a second element" means that the first element can be etched and the second element can act as an etch stop.

The terms "about", "substantially", "approximately" and variations thereof are intended to include the degree of error associated with a measurement of the particular quantity based on the equipment available at the time of filing the application. For example, “about” can encompass a range of ± 8% or 5% or 2% of a given value.

As previously mentioned herein, for the sake of brevity, conventional techniques relating to fabrication of semiconductor devices and integrated circuits (ICs) may or may not be described in detail herein. However, as background information, a more general description of the semiconductor device manufacturing processes that may be used in implementing one or more embodiments of the present invention is now provided. While specific manufacturing processes used in practicing one or more embodiments of the present invention may be individually known, the described combination of processes and / or the described resulting structures are unique to the present invention. Thus, in the unique combination of the operations described in connection with the manufacture of a semiconductor device according to the present invention, a variety of individually known physical and chemical processes are employed that are performed on a semiconductor substrate (e.g., a silicon substrate), some of which are in the immediately following sections.

In general, the various processes used to form a microchip that is packaged into an IC fall into four common categories, namely film deposition, removal / etching, semiconductor doping, and patterning / lithography. Deposition is any process that involves growing a material onto the wafer, coating it with a material, or otherwise transferring a material onto the wafer. Available technologies include physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), molecular beam epitaxy (MBE) and, more recently, atomic layer deposition (ALD). The remove / etch is any process that removes material from the wafer. Examples include etching processes (either wet or dry etching processes) as well as chemical mechanical planarization (CMP) and the like. Semiconductor doping is the modification of electrical properties by doping, for example, transistor sources and drains, generally by means of diffusion and / or by means of ion implantation. These doping processes are followed by annealing in the oven or rapid thermal annealing (RTA). The annealing serves to activate the implanted dopants. Layers of both conductors (e.g. made of polysilicon, aluminum, copper etc.) and of insulators (e.g. made of various forms of silicon dioxide, silicon nitride etc.) are used to connect and disconnect transistors and their components. Selective doping of different areas of the semiconductor substrate enables the conductivity of the substrate to be changed when a voltage is applied. By creating structures from these various components, millions of transistors can be fabricated and wired together to form the complex circuitry of a modern microelectronic device. Semiconductor lithography involves the formation of three-dimensional relief images or structures on the semiconductor substrate for a subsequent transfer of the structure to the substrate. In semiconductor lithography, structures are formed using a photosensitive polymer called photoresist. To create the complex structures that make up a transistor and the many wirings that connect the millions of transistors in a circuit, lithography steps and steps for transferring the etch structure are repeated many times. Each structure that is printed on the wafer is aligned with the previously formed structures, and the conductors, insulators and selectively doped areas are gradually fabricated to form the final unit.

The flowchart and the block diagrams in the figures represent possible implementations of manufacturing and / or operating methods according to various embodiments of the present invention. Various functions / processes of the method are represented by blocks in the flowchart. In some alternative implementations, the functions mentioned in the blocks may take place out of the order noted in the figures. For example, two blocks shown in sequence may in fact be executed essentially simultaneously, or the blocks may sometimes be executed in the reverse order, depending on the functionality involved.

The descriptions of the various embodiments of the present invention have been presented for purposes of illustration and are not intended to be exhaustive or limited to the embodiments described. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein was chosen to best explain the spirit of the embodiments, practical application, or technical improvement over technologies found in the marketplace, or to enable others skilled in the art to understand the embodiments described herein.

Claims (25)

A method of making a dielectric layer, the method comprising: Depositing a first starting material on a substrate, the first starting material having a cyclic carbosiloxane group with a six-membered ring; Depositing a second starting material on the substrate, wherein the first starting material and the second starting material form a preliminary layer on the substrate and wherein the second starting material comprises silicon, carbon and hydrogen; and Applying energy from an energy source to the preliminary layer to form a porous dielectric layer. Procedure according to Claim 1 wherein the porous dielectric layer comprises at least 30 atomic percent carbon. Procedure according to Claim 1 wherein the substrate is a structured substrate and the porous layer is deposited in trenches within the structured substrate. Procedure according to Claim 1 which further comprises an action of a nitrogen-containing raw material on the preliminary layer. Procedure according to Claim 4 wherein the nitrogen-containing feedstock comprises ammonia, nitrous oxide, or a combination thereof. Procedure according to Claim 1 wherein the porous dielectric layer further comprises about 1 atom% to about 4 atom% nitrogen. Procedure according to Claim 1 wherein the porous dielectric layer has a k value of from about 2.2 to about 2.8. A method for producing a dielectric layer, the method comprising: depositing a first starting material on a substrate, the first starting material having the following structure:

and wherein a, b, c, d, e and f are each independently an alkyl group or an alkenyl group; Depositing a second starting material on the substrate, wherein the first starting material and the second starting material form a preliminary layer on the substrate and wherein the second starting material comprises a linear carbosiloxane; and applying an energy source to the preliminary layer to form a porous dielectric layer. Procedure according to Claim 8 wherein the alkyl group has a methyl group, an ethyl group, a propyl group, a butyl group or a pentyl group. Procedure according to Claim 8 wherein the alkenyl group has an ethenyl group, a propenyl group, a butenyl group or a pentenyl group. Procedure according to Claim 8 , wherein the linear carbosiloxane has the following structure:

and wherein g, h, i, j, k and l are each independently an alkyl group, an alkenyl group or an alkoxy group. Procedure according to Claim 8 , wherein a ratio of carbon to oxygen in the second raw material is higher than 1. Procedure according to Claim 8 which further comprises an action of a nitrogen-containing raw material on the preliminary layer. A method of making a dielectric layer, the method comprising: Depositing a first starting material on a substrate, the first starting material having a cyclic carbosiloxane group; Depositing a second starting material on the substrate, wherein the first starting material and the second starting material form a preliminary layer on the substrate and wherein the second starting material comprises a carbosilane with a ratio of carbon to silicon which is higher than 3: 1; Applying an energy source to the preliminary layer to form a porous dielectric layer. Procedure according to Claim 14 which further comprises an action of a nitrogen-containing raw material on the preliminary layer. Procedure according to Claim 14 wherein the porous dielectric layer comprises at least 30 atomic percent carbon. Procedure according to Claim 14 wherein a ratio of carbon to silicon in the second raw material is higher than 4: 1. Procedure according to Claim 14 wherein the energy source comprises thermal energy, ultraviolet light, microwave energy, electron beam energy, ion beam energy, or catalytic species. A porous dielectric layer comprising: a covalently bonded network comprising atoms of silicon, oxygen, carbon and hydrogen; a cyclic carbosiloxane group; and a bridging Si-CH ₂ -Si group. Porous dielectric layer after Claim 19 wherein the porous dielectric layer comprises at least 30 atomic percent carbon. Porous dielectric layer after Claim 19 wherein the porous dielectric layer comprises from about 35 atomic percent to about 50 atomic percent carbon. Porous dielectric layer after Claim 19 wherein the dielectric layer has a k value of from about 2.2 to about 2.8. A porous dielectric layer comprising: a covalently bonded network comprising atoms of silicon, oxygen, carbon, hydrogen and nitrogen; a cyclic carbosiloxane group; and a bridging Si-CH ₂ -Si group. Porous dielectric layer after Claim 23 wherein a content of nitrogen comprises about 1 atom% to about 4 atom%. Porous dielectric layer after Claim 23 wherein the porous dielectric layer comprises at least 30 atomic percent carbon.

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